Palmar arch backflow following radial forearm free flap harvest

Background: Most surgeons advocate an Allen test (for occlusion of the radial or ulnar artery) and Doppler ultrasound examination before harvesting a forearm flap. In this study we attempted to correlate the results of these tests with intraoperative measurement of backflow pressure in the radial artery stump. Method: Stump pressures were measured in 30 patients after the flap had been harvested and were compared with preoperative assessment and intraoperative measurements of mean arterial pressure (MAP). Results: Mean arterial backflow pressure (MABP) in the arterial stump varied from 27 to 55 mmHg (mean 40.5). The ratio of this value to the mean arterial pressure ranged from 0.39 to 0.89 (mean 0.59) and exceeding 0.5 in 21 patients (70%). There was no correlation between this ratio and the preoperative assessment. Conclusions: These findings suggest that in the presence of a satisfactory Allen test and Doppler examination, there is adequate pressure in the palmar system to maintain vascular integrity of the donor hand after sacrifice of the radial artery. Despite the possibility of anatomical variants, the routine use of more invasive imaging is unnecessary.